In solar heating apparatus in which heat absorbing fluid is conducted through tubes or channels, there are many ways of feeding the fluid into and out of the channels. The channel can be in the form of a single serpentine channel for maximum exposure of the fluid to solar heating, but this arrangement has the disadvantage of low flow rate. For maximum flow rate the fluid is conducted simultaneously through multiple tubes between an inlet manifold and an outlet manifold. This type of structure is usually made by connecting small tubes between two larger manifold tubes, which requires a large number of joints to be fitted and sealed. A considerable amount of labor is involved and the cost is high.